1. Field of the Disclosure
The present disclosure relates to a liquid crystal display (LCD) device and, more particularly, to an LCD device capable of driving a light emitting diode (LED) provided to turn on a fluorescent lamp provided as a light source in darkness by using an induced voltage without employing a driving circuit to thus minimize a fabrication cost and power consumption.
2. Description of the Related Art
In general, the application coverage of a liquid crystal display (LCD) extends because of its characteristics that it is lighter, thinner, and driven at a low power consumption. Thus, the LCD is commonly used as a means for displaying images in mobile computers, mobile phones, office automation equipment, or the like.
The LCD displays a desired image on its screen by controlling the amount of transmission of light according to a video signal applied to a plurality of control switching elements arranged in a matrix form.
The LCD includes a liquid crystal panel including a color filter substrate, an upper substrate, and a thin film transistor (TFT) substrate, a lower substrate, which face, between which and a liquid crystal layer is formed, and a driver that supplies a scan signal and image information to the liquid crystal panel to operate the liquid crystal panel.
The LCD is not a self-emissive display device which does not emit light by itself, so it requires a light source for providing light to the liquid crystal panel. Thus, the LCD includes a backlight assembly including a light source to supply light to the liquid crystal panel, and a light guide plate and an optical sheet to convert light emitted from the light source into white uniform plane light.
A light source for generating light in the backlight assembly includes a CCFL (Cold Cathode Fluorescent lamp), an EEFL (External Electrode Fluorescent Lamp), the LED, or the like.
The general LCD will now be described with reference to the accompanying drawings.
As shown in FIG. 1, the general LCD includes a liquid crystal panel 1, a plurality of fluorescent lamps 2 disposed under the liquid crystal panel and supplying light to the liquid crystal panel 1, an optical sheet 11 for converting light emitted from the fluorescent lamps 2 and supplying the converted light to the liquid crystal panel 1, a lower cover 9 for receiving the plurality of fluorescent lamps, and a timing controller 10 disposed on a rear surface of the lower cover 9 and driving the liquid crystal panel 1.
A light emitting diode (LED) 8 for improving dark lighting is mounted on the timing controller 10, and an LED driving unit (not shown) for driving the LED 8 is also mounted thereon. A hole 10a is formed at a position of the lower cover 9 corresponding to the LED 8 to allow light emitted from the LED 8.
The general LCD having such configuration is advantageous in that the fluorescent lamps 2 are turned on in darkness by using light emitted from the LED 8, but disadvantageous in that power is consumed to drive the LED driving unit to increase power consumption. Also, the LED driving unit includes a plurality of circuit elements, increasing the size of the timing controller 10 on which the LED driving unit is mounted and increasing the fabrication cost. In addition, when the fluorescent lamps 2 are turned on in darkness, if a sequence related to a point of time at which a power voltage is applied to the fluorescent lamps 2 and a sequence related to a point of time at which the LED 8 is driven are not matched, the fluorescent lamps 2 would not be turned on.